1. Technical Field
The present invention relates to a flat bed scanner apparatus, and more particularly, to an improved flat bed scanner apparatus for scanning sheets having a stacked-sheet feeder which is separate from a flat bed cover, causing the flat bed cover to be much easier to open and close.
2. Related Art
A conventional scanner is designed to convert data recorded on paper into a computer-compatible electronic form. The data recorded on a document can be scanned as follows. An amount of light is first transmitted to the document from a source. As a result, the image data on the document causes some of that light to be reflected in a particular pattern. The pattern of reflected light is then supplied to a fixed array of light sensors through an intermediate image reduction mirror. The light sensors in the array can be charge-coupled devices (CCD) or contact image sensors (CIS). Then circuitry in the scanner senses the status of each sensing element in the array one by one, in order to register the brightness of each point in each individual scan line. After the scanner has collected and arranged the data from each sensor, the next line of data can be read.
A first type of scanner has a flat bed cover and a flat bed platen for scanning a single sheet but does not have an automatic sheet feeder. A user scans a sheet by lifting the flat bed cover, placing the sheet face down onto the flat bed platen, and then closing the flat bed cover. Then the user typically presses a "start" button in order to cause the scanner to scan the sheet. One problem with this type of scanner is the fact that it requires a lot of work to scan a stack of sheets. For each sheet to be scanned, a user must lift the cover, place the sheet onto the flat bed platen, lower the cover, press the "start" button, lift the cover again, and remove the sheet. This procedure can be time consuming and tedious when a user needs to scan a large stack of sheets.
A second type of scanner creates a new problem while it attempts to solve the problem above. The second scanner type includes the flat bed platen and flat bed cover of the first type of scanner and, additionally, has an automatic stacked-sheet feeder. This scanner type has an automatic stacked-sheet feeder which either is attached directly to the upper portion of the flat bed cover or is located immediately above the flat bed cover. In either arrangement, the stacked-sheet feeder is necessarily lifted or moved whenever the flat bed cover is lifted, in order to place or remove a sheet onto the flat bed platen. The stacked-sheet feeder can automatically scan a stack of sheets, one at a time. The stacked-sheet feeder typically has a tray for sheets and will feed a stack of sheets into the scanner, one at a time, until all sheets in the tray have been scanned. This appears to eliminate the problem of the first type of scanner. That is, a user does not need to perform the following procedure for each sheet to be scanned: lift a cover, place a sheet on the platen, close the cover, then press the "start" button, lift the cover again, and then remove the sheet from the platen. Unfortunately, the second type of scanner created a new problem. The paper tray, rollers, sensors, and other components associated with an automatic stacked-sheet feeder can be unnecessarily heavy. The problem with the scanners having an automatic stacked-sheet feeder is the fact that the cover can be heavy and difficult to lift. When a user wants to scan a single sheet on the flat bed platen, the user must lift the heavy cover. A user will want to user the flat bed platen in lieu of the stacked-sheet feeder if the document to be scanned is a page in a book. Lifting the heavy cover and stacked-sheet feeder is extremely inconvenient and unnecessarily burdensome. Some examples of this type of scanner are disclosed in U.S. Pat. No. 5,537,219 for Movable Image Reading Apparatus issued to Morikawa et al. and U.S. Pat. No. 5,379,095 for Image Reading Apparatus With the Optical Reading Units and Photoelectric Conversion Device Mounted on a Common Guide Member issued to Oishi.
Another problem with the aforementioned second type of scanner is the fact that it requires a lot of space when the cover is lifted. Also, the scanner apparatus itself can be heavy and difficult to move. In addition, the sheet feeder system can occupy a lot of space and constitute an inefficient use of space, even when the cover is closed.
Some scanners and other devices use movable mirrors. Some examples of devices with movable mirrors are disclosed in U.S. Pat. No. 5,638,189 for Raster Scanner, Mirror Supporting Structure of the Same and Method for Adjusting Mirror Angle Using the Structure issued to Yanagisawa and U.S. Pat. No. 5,485,263 for Optical Path Equalizer issued to Bjorner et al.
Other examples of scanner devices are disclosed in U.S. Pat. No. 5,513,017 for Automatic Document Imaging Mode Selection System issued to Knodt et al., U.S. Pat. No. 5,523,848 for Ink Jet Printing Device and Plain Paper Facsimile Apparatus Using the Same issued to Musso et al., and U.S. Pat. No. 5,075,539 for Method and Apparatus for Adjusting the Position of Image Reading Equipment issued to Shiraishi.
Some devices having a sheet feeder are disclosed in U.S. Pat. No. 5,313,312 for Color Image Processing Apparatus Capable of Discriminating Attributes of Originals Fed by a Feeder issued to Yamada, U.S. Pat. No. 4,958,825 for Paper Let-out Apparatus issued to Onomoto et al., U.S. Pat. No. 5,100,022 for Sheet Container and Sheet Dispenser Apparatus issued to Fukudome et al., and U.S. Pat. No. 5,104,109 for Paper Sheet Delivery/Stacking Control System Using Fuzzy Inference issued to Kubo.
Accordingly, I have discovered that it would be desirable to enhance scanner construction by providing an improved flat bed scanner apparatus with a stacked-sheet feeder and a flat bed cover that is easier to operate, with a smaller design in order to more efficiently utilize available space and cause the scanner apparatus to be easier to move.